Ultimately it will depend on the size and shape of the exhaust port at the cylinder wall. Depending on how it was done can greatly effect where the power band is. As you mention, you can go too far (raise the port too high) and lose a good bit of low end performance for (possibly) high RPM gains. Worst concern would be loss of trapping efficiency if the flow patterns get altered too much (for whatever reason).

I am not familiar with Mercs, but hopefully there are many on this site that have some good mod porting specs for these engines.

its just a ported exhaust ports to smooth out the power range and let the exhaust exit faster gona give it lower exhaust gas temps (egt) for sure kinda like adding an exhaust to a 2stroke dirt bike power gains in low and mid range better throttle response how much hp on a outboard not for sure on a dirtbike about 3-5 hp which is alot when dirtbikes only have around 40-60 lol so thats a answer for someone else lol tty today some time bro

Been wanting to ask this for a couple weeks but just now got around to get some pictures to post with it. I have a 2.4 200 that I am getting rebuilt. When I removed the exhaust plate there appears to be A LOT of port work done. Can someone tell me if this appears to be too much taken off and what real gains to you acheive by doing this? Thanks

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